Syntheses, structures and fluorescence properties of three rare-earth containing docosatungstates

Hailou Li; Yajie Liu; Rui Zheng; Xing Ma; Lijuan Chen; Junwei Zhao

doi:10.1016/j.saa.2017.01.016

Syntheses, structures and fluorescence properties of three rare-earth containing docosatungstates

Spectrochim Acta A Mol Biomol Spectrosc. 2017 Apr 5:176:114-122. doi: 10.1016/j.saa.2017.01.016. Epub 2017 Jan 9.

Authors

Hailou Li¹, Yajie Liu¹, Rui Zheng¹, Xing Ma¹, Lijuan Chen², Junwei Zhao³

Affiliations

¹ Henan Key Laboratory of Polyoxometalate Chemistry, Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, PR China.
² Henan Key Laboratory of Polyoxometalate Chemistry, Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, PR China. Electronic address: [email protected].
³ Henan Key Laboratory of Polyoxometalate Chemistry, Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, PR China; State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, PR China. Electronic address: [email protected].

PMID: 28088689
DOI: 10.1016/j.saa.2017.01.016

Abstract

Three rare-earth containing docosatungstates Na₃H₂[RE(H₂O)₄][RE(H₂O)₅]₂[W₂₂O₇₄H₂]·36H₂O [RE=Dy^III (1), Ho^III (2), Y^III (3)] have been synthesized by reaction of Na₂WO₄·2H₂O, dimethylamine hydrochloride (DMAHC) and RE(NO₃)₃·6H₂O in the aqueous solution and characterized by elemental analyses, IR spectra, thermogravimetric (TG) analysis, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. 1-3 are isomorphous and each molecular unit consists of a S-shaped docosatungstate [W₂₂O₇₄H₂]^14- polyoxoanion with two supporting [RE(H₂O)₅]³⁺ cations and one disordered [RE(H₂O)₄]³⁺ cation. The [W₂₂O₇₄H₂]^14- polyoxoanion can be viewed as combination of two hendecatungstate [W₁₁O₃₈H]^9- subunits in the staggered fashion by sharing two μ₂-O atoms. The TG curves of 1-3 reveal the one-step weight loss between 25°C to 700°C. Moreover, both 1 and 2 demonstrate the characteristic luminescence emission behaviors of the corresponding RE³⁺ ions and their lifetime decay curves can be well fitted to the double exponential function. In addition, the CIE chromaticity coordinates of 1 and 2 have been obtained based on their corresponding emission spectra, and their dominant wavelengths and color purities have been also calculated.

Keywords: Isopolytungstate; Photoluminescence; Polyoxometalate; Rare earth.